1. Field of the Invention
The present invention relates to a communication apparatus and a congestion regulation control method. More particularly, the invention relates to a communication apparatus which communicates with a plurality of stations and executes regulation control at the time of congestion, and a congestion regulation control method which communicates with a plurality of stations and executes regulation control at the time of congestion.
2. Description of the Related Art
Recently, the loads of communication networks are increasing with an increase in the number of subscribers. For instance, an overloaded state is likely to occur in a system that includes a station which is always accessed by a plurality of stations, such as an HLR (Home Location Register) station of a mobile communication network.
When such an overloaded state occurs, the call connecting capability falls, thereby adversely affecting the overall network. It is therefore necessary to reduce the load without decreasing the service quality by minimizing the adverse influence. A typical conventional technique searches for a station whose traffic is heavy when congestion occurs and controls the regulation of that station.
Because the prior art always regulates a station whose traffic is heavy, however, the regulation control is not flexible. When a disaster occurs, it is necessary to give priority to signals from stations in a disaster area where the traffic is heavy and regulate stations in light-traffic areas. The prior art does not execute flexible regulation control as to set signals from stations in such an important area free of regulation.
The prior art performs regulation control only on a target which suffers an excessive increase in the traffic of received signals. However, system congestion is not always caused by the traffic of received signals. With a high traffic which is not heavy enough to cause congestion, for example, a process of maintaining and managing the system may be invoked, thus increasing the Central Controller (hereinafter referred to as “CC”) occupancy rate. This may result in congestion.
The prior art has a shortcoming such that communication by a subscriber is regulated even when congestion is caused by such a maintenance and operation process.